RESUMEN
Polyacrylamide gel electrophoresis (PAGE) coupled with mass spectrometry has been well established for separating, identifying and quantifying protein mixtures from cell lines, tissues or other biological samples. The copolymerization process of acrylamide and bis-acrylamide is the key to mastering this powerful technique. In general, this is a vinyl addition reaction initiated by free radical-generating reagents such as ammonium persulfate (APS) and tetramethylethylenediamine (TEMED) under basic pH and degassing experimental condition. We report herein a photocatalytic polymerization approach that is based on photo-generated hydroxyl radicals with nanoparticles of titanium dioxide. It was shown that the polymerization process is greatly accelerated in acidic condition when ultraviolet light shots on the gel solution containing TiO2 nanoparticles without degassing. This feature makes it very useful in preparing Triton X-100 acid urea (TAU) gel that has been developed for separating basic proteins such as histones and variants in acidic experimental condition. Additionally, the presence of titanium dioxide in the gel not only improves mechanistic property of gels but also changes the migration pattern of different proteins that have different affinities to titanium dioxide.
Asunto(s)
Acrilamida/química , Caseínas/aislamiento & purificación , Electroforesis en Gel de Poliacrilamida/métodos , Histonas/aislamiento & purificación , Titanio/química , Acrilamida/efectos de la radiación , Sulfato de Amonio/química , Animales , Etilenodiaminas/química , Hígado/química , Espectrometría de Masas , Octoxinol/química , Fosforilación , Procesos Fotoquímicos , Polimerizacion , Pironina , Ratas , Rayos Ultravioleta , Urea/químicaRESUMEN
A simple, rapid and localizable photochemical process for the preparation of hydrophilic coated capillary and silica-based monolithic capillary columns is described. The process involves the free radical polymerization of acrylamide monomers onto acrylate pre-activated silica surface triggered by UV photoinitiation. The experimental conditions (monomer content, time of irradiation) were optimized on silica monolithic columns by monitoring the evolution of the chromatographic properties (retention, permeability, efficiency) in HILIC mode using a set of nucleosides as test solutes. Compared to thermal polymerization process, the photoinitiation allows the preparation of highly retentive and efficient HILIC monolithic columns in less than 10min of irradiation. This process was then successfully applied to the surface coating of fused silica capillary walls. In addition to its relative high stability and ability to reduce the electroosmotic flow, this polyacrylamide coating is localizable. Benefits of this localizable photochemical process are highlighted through the conception of an in-line integrated bimodal microseparation tool combining a SPE preconcentration step on a photografted silica monolith and an electrokinetic separation step in a polyacrylamide photopolymerized capillary section. Two neuropeptides are used as model solutes to illustrate the suitability of this approach.
Asunto(s)
Acrilamida/química , Resinas Acrílicas/química , Dióxido de Silicio/química , Acrilamida/efectos de la radiación , Cromatografía Liquida , Electroforesis Capilar , Encefalina Leucina/análisis , Encefalina Metionina/análisis , Interacciones Hidrofóbicas e Hidrofílicas , Nucleósidos/análisis , Polimerizacion , Dióxido de Silicio/efectos de la radiación , Rayos UltravioletaRESUMEN
We study the shrinkage in acrylamide based photopolymer by measuring the Bragg detuning of transmission diffraction gratings recorded at different slant angles and at different intensities for a range of spatial frequencies. Transmission diffraction gratings of spatial frequencies 500, 1000, 1500 and 2000 lines/mm were recorded in an acrylamide based photopolymer film having 60 ± 5 µm thickness. The grating thickness and the final slant angles were obtained from the angular Bragg selectivity curve and hence the shrinkage caused by holographic recording was calculated. The shrinkage of the material was evaluated for three different recording intensities 1, 5 and 10 mW/cm2 over a range of slant angles, while the total exposure energy was kept constant at 80 mJ/cm2. From the experimental results it can be seen that the shrinkage of the material is lower for recording with higher intensities and at lower spatial frequencies.
Asunto(s)
Acrilamida/química , Acrilamida/efectos de la radiación , Holografía/métodos , Ensayo de Materiales/métodos , Fotoquímica/métodos , Refractometría/métodos , Módulo de Elasticidad , LuzRESUMEN
The development of suitable recording media for applications such as holographic optical elements and holographic data storage are of significant research and commercial interest. In this paper, a photopolymer material developed by Bayer MaterialScience is examined using various optical techniques and then characterised using the Non-local Photo-polymerization Driven Diffusion model. This material demonstrates the capabilities of a new class of photopolymer offering high index modulation, full colour recording, high light sensitivity and environmental stability. One key result of this study is the material's high spatial frequency resolution, indicating a very low non-local effect, thus qualifying it as a very good storage medium.
Asunto(s)
Acrilamida/química , Acrilamida/efectos de la radiación , Modelos Químicos , Alcohol Polivinílico/química , Alcohol Polivinílico/efectos de la radiación , Color , Simulación por Computador , Luz , Ensayo de Materiales , Refractometría , Dispersión de RadiaciónRESUMEN
High-spatial-frequency fringes associated with reflection holographic optical elements are difficult to obtain with currently available recording materials. In this work, holographic reflection gratings were stored in a polyvinyl alcohol/acrylamide photopolymer. This material is formed of acrylamide photopolymer, which is considered interesting material for optical storage applications such as holographic memories. The experimental procedure for examining the high-spatial-frequency response of this material is explained, and the experimental results obtained are presented. With the aim of obtaining the best results, the performance of different material compositions is compared.
Asunto(s)
Acrilamida/química , Acrilamida/efectos de la radiación , Almacenamiento y Recuperación de la Información/métodos , Alcohol Polivinílico/química , Alcohol Polivinílico/efectos de la radiación , Refractometría/instrumentación , Refractometría/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Luz , Fotoquímica/métodos , Polímeros/química , Polímeros/efectos de la radiaciónRESUMEN
Molecular diffusion effects have been widely studied inside photopolymers for holographic applications. Recently some works have focused on low spatial frequencies to evaluate in real time the monomer diffusion effects. Assuming a Fermi-Dirac function-based profile, we have fitted the diffracted intensities, reflected and transmitted (up to the 8th order), to obtain the phase and surface profile of the recorded gratings. We have studied the influence of diffusion in polyvinyl-alcohol/acrylamide for the range of spatial frequencies between 2 lines/mm and 6 lines/mm. We have demonstrated the influence of the spatial frequency on the magnitude and sign of the material volume variations. We also studied in dark the evolution of the grating shape. We show that it is possible to achieve diffractive gratings with diffraction efficiency in the first order near 35% if the in dark evolution is taken into account. Furthermore we present a method to calculate the monomer diffusivity in photopolymers. The differential equation is deduced and solved, and experimental average value is obtained (D=1.1 x 10(-8) cm(2)s(-1)).
Asunto(s)
Acrilamida/química , Modelos Químicos , Nefelometría y Turbidimetría/métodos , Alcohol Polivinílico/química , Refractometría/métodos , Acrilamida/efectos de la radiación , Simulación por Computador , Luz , Ensayo de Materiales , Alcohol Polivinílico/efectos de la radiación , Dispersión de RadiaciónRESUMEN
Holographic data pages were multiplexed in different thickness layers of a polyvinyl alcohol/acrylamide photopolymer. This material is formed of acrylamide photopolymers, which are considered interesting materials for recording holographic memories. A liquid crystal device was used to modify the object beam and store the data pages. A peristrophic multiplexing method is used to store a large number of data pages in the same spot in the material. The bit error rate was calculated fitting the histograms of the images to determine what parameters improve the quality of the images.
Asunto(s)
Acrilamida/química , Holografía/instrumentación , Almacenamiento y Recuperación de la Información , Alcohol Polivinílico/química , Procesamiento de Señales Asistido por Computador/instrumentación , Acrilamida/efectos de la radiación , Fotoquímica/instrumentación , Fotoquímica/métodos , Alcohol Polivinílico/efectos de la radiaciónRESUMEN
Linear anionic polyacrylamide (PAM) has been used in irrigation practices as a flocculating agent to minimize water losses through seepage in earthen canals. The stability of PAM is of concern because of the possibility of acrylamide (AMD) monomer release during environmental weathering. Aqueous solutions of commercial PAM mixed with ferric sulfate, subjected to simulated and natural sunlight irradiation, showed polymer chain scission and release of the AMD monomer. At acid/neutral pH, the amount of AMD released was directly related to the concentration of ferric ion and the irradiation time. At alkaline pH (approximately 8), PAM/Fe(3+) mixtures were stable under irradiation. PAM chain scission involved the hydroxyl radical, but specific AMD release appeared to require PAM-bound iron. Low iron concentrations and alkaline pH of irrigation water would limit AMD release. Residual monomer in PAM can contribute AMD to irrigation water, but concentrations would remain below the U.S. EPA drinking water standard of 0.5 ppb.
Asunto(s)
Acrilamida/química , Acrilamida/efectos de la radiación , Hierro/química , Hierro/efectos de la radiación , Luz Solar , Aniones , Compuestos Férricos/química , Concentración de Iones de Hidrógeno , Hierro/análisis , Soluciones , AguaRESUMEN
Serum albumin, one of the most abundant serum proteins, blocks the expression of other important biomarkers. The objective of this study is to remove serum albumin effectively by using solid-phase extraction (SPE) in microfluidic devices. Photo-polymerized adsorbent as a stationary phase of SPE was used to remove bovine serum albumin (BSA). The adsorption capacity was examined with the effect of pH and concentration in BSA solution, and adjustment of monomer concentration such as hydrophilic 2-acrylamido-2-methyl-1-propanesulfonic acid and acrylamide in the adsorbent. The effect of hydrophobic butyl methacylate on BSA adsorption was also studied. Selective removal in a bicomponent with BSA and bovine gamma-globulin was performed by adjusting the pH as required.
Asunto(s)
Albúmina Sérica Bovina/aislamiento & purificación , Extracción en Fase Sólida/métodos , Acrilamida/efectos de la radiación , Acrilamidas/efectos de la radiación , Adsorción , Alcanosulfonatos/efectos de la radiación , Concentración de Iones de Hidrógeno , Metacrilatos/efectos de la radiación , Técnicas Analíticas Microfluídicas/instrumentación , Microscopía Electrónica de Rastreo , FotoquímicaRESUMEN
By dynamic method under UV irradiation, commercial melt-blown polypropylene (PPMB) filter element was modified with acrylamide (AAm) using benzophenone (BP) as initiator. Attenuated total reflection-Fourier transform infrared spectroscopy and scanning electron microscope verified that polyacrylamide chain was grafted on the fiber surface of PPMB filter element. Elemental content analysis with energy dispersive X-ray of fibers revealed that the polymerization content in the inner part of filter element was relatively higher than that in the outer. Degree of grafting changed with initiator concentration, monomer concentration, reaction temperature and reached 2.6% at the reaction condition: CBP=0.06 mol/L, CAAm=2.0 mol/L, irradiation time: 80 min, temperature: 600 degrees C. Relative water flux altered with the hydrophilicity and pore size of filter element. In the antifouling test, the modified filter gave greater flux recovery (approximately 70%) after filtration of the water extract of Liuweidihuang, suggesting that the fouling layer was more easily reversible due to the hydrophilic nature of the modified filter.